(US5026946-A)      Prodn of an at least 2C hydrocarbon prod including ethylene from a CH4 contg gaseous paraffinic hydrocarbon feedstock comprises heating under elevated pressure in a preheating zone a mixt of the feedstock and 02 in an amt of at least 5 mol % to a temp to effect spontaneous reaction. Prheating and mixing are effected so that 02 consumption is prevented and a flashback of the reaction to form a diffusion flame at the point of gaseous mixing is prevented. Then, the feedstock mixt is allowed to react spontaneously under adiabatic conditions in a reaction zone.    Pref the feedstock and 02 are mixed at ambient temp and rapidly heated to the spontaneous reaction temp in a region where the gas velocity exceeds the propagation velocity of the reaction. (5pp)c    (EP302665-B)      A process for the production of a C2 and higher hydrocarbon product including ethylene from a methane-containing gaseous paraffinic hydrocarbon feedstock which process comprises heating under elevated pressure in a pre-heating zone a mixture of the feedstock and oxygen in an amount of at least 5% mol to a temperature sufficient to cause spontaneous reaction, the pre-heating and mixing being effected in a manner such that (i) substantial oxygen consumption is avoided, and (ii) a "flash-back" of the reaction to form a diffusion flame at the point of gaseous mixing is prevented, and thereafter in a reaction zone allowing the feedstock mixture to spontaneously react, the reaction zone being maintained under adiabatic conditions. (9pp)y    (DE3869267-G)      A product (II) comprising C2 and higher hydrocarbons including ethylene is obtd. from a methane-contg. gaseous paraffinic hydrocarbon feedstock (I) by (a) heating at elevated pressure in a pre-heating zone a mixt. of (I) and at least 5 mole % oxygen to a temp. sufficient to cause spontaneous reaction, and (b) allowing the mixt. to react in a reaction zone. Pre-heating and mixing are effected in a manner such that (i) substantial oxygen consumption is avoided, and (ii) a flashback of the reaction to form a diffusion flame at the point of gaseous mixing is avoided.    ADVANTAGE -   High methane conversion and high selectivity to ethylene and ethane are obtd. without the use of a diluent. No significant amt. of acetylene is formed, and a quench step is not necessary. Carbon monoxide and hydrogen are obtd. as valuable byproducts.